Method of making lock washers



Feb. 16, 1932.

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- CORPORATION OI DELAWARE IE'IKOD OI MAKING LOOK w Application med December 16, 1887. Serial R0. 240,898.

This invention relates to a new method of producing lock washers of the twisted tooth t pe, for example that shown in my Patent 0. 1,419,564 of June 13, 1922.

5 Heretofore such washers have been made by punching from thin flat stock an annular blank having external or internal prongs, and twistin the prongs to project out from the plane the blank. Considerable scrap material was discarded. 1

The object of the present invention isto provide a method whereby washers, having either external or internal prongs, are prof- 1 duced rapidly and with little or no waste.

metal. The important thing in this a plication is the method of procedure, not t e particular means by which the method shall be produced.

The claimed method is capable of bein erformed by hand and I first demonstrate 1t that way. However, the several operations conceived, and coordinated so that by the employment of suitable mechanical means a single feed of ribbon metal is made to yield as many as one million washers per day. The means of operating will be described as a manual means.

Fig. 1 is a plan view of a stock strip with serrated edges forming regular prongs, showin g also the small punchings therefrom.

Fig. 2 is an edge view of the strip with certain of its prongs twisted out of the plane of the strip.

Fig. 3 is a side view of a strip formed into helical shape, with external prongs.

Fig. 4 is a similar view of a helical strip having internal prongs.

Figs. 5 and 6 are side views of individual helical Washer members having external and internal prongs respectively.

Fig. 7 shows in edge view the washer members of Figs. 5 and 6 after they have been compressed into substantially flat circular form.

Fig. 8 shows the way in which the contigu- The method, considered in its broader as pect, comprises a series of acts performedupon a long ribbon, or strip or band of sheet their teeth twisted are used when that characterize it have been individually punched to form two stock strips having complemental edges serrated and forming relatively narrow prongs, the portion used for each washer having a relatively wider prong shaped to provide an interlocking joint.

Primarily the method consists in taking a stock strip 1, formed with a serrated edge characterized by regular prongs 1a, twist- .ing all of the prongs, or certain of them, as [the case may be, axially out of the plane of the strip, as at 2 in Fig. 2. Washers with all permanent locking is desired.

Twisting part of them produces a washer that has enough biting teeth to efl'ectively look a nut against unscrewing in all condi tions of ordinary use, yet it can be easily unscrewed by a hand-operated wrench.

After the teeth are twisted the strips are bent into helical shape, the prongs directed outwardly from the imaginary axis of the helix 3 for producing external toothed washers, or directed radially inward, as at 4, Fig. 4, for internal toothed washers. The helical strip is then severed at the end 5 of each convolution. Individual washer members of helical form, shown in Figs. 5 and 6 are thus produced. Such helical members are con ceivably capable of being usedin their existing condition as lock washers, because their shape will be automatically converted from helical to annular when the nut to be locked is screwed down.

However, the method is in practice pref- 9 erably carried forward to include pressing the helical washer member into annular form so as to bring its severed ends together, Fi s.

8 and 9. The method may also include uniting the severed ends in various ways, with- 100 out departing from the claimed invention, for example, the contiguous ends may be fused together by spot welding or butt welding, as at 6, or they may be mechanicall interlocked by means of joints of dovetail or equivalent construction, as at 7 or 7a.

To provide ample metal area for such dovetail joints, one prong 8 of each washer is preferably wider than the others. The ultimate location of the severed joints is indicated in Figs. 1 and 11 by dotted lines.

In each instance the base material employed in carrying out this method is a strip 1 that has been formed with a serrated edge presenting re ar prongs 10. Such base material strip is transformed into lock washers by the acts of tooth-twisting, helical bending, severing, flattenin and end jointing. A-roll or coil of para el edged ribbon metal, say, several hundred feet long can be speedily converted by punching along the zigza line 9, Fig. 11, into twice that number 0% linear feet of stock strips 1. Either one of the two resulting stock strips, 10, 12 can at will be made into either external or internal toothed washers. The same method is then followed with another length of rib bon metal and the operation is practically continuous.

There is onl a slight amount of waste when narrow ri bon metal is punched along one edge, as in Fig. 1, to roduce a base material stock strip, since t e punchings 12 are -not a loss, being wanted for other practical uses. There is no waste whatsoever when parallel-edged ribbon metal, Fig. 11, is used to form the base material strip, 10 and 12.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. The method of making a lock washer having radially directed, axially twisted locking teeth, which comprises severing a strip of ribbon metal lengthwise on an irregular line producing two stock strips having teeth projecting outwardly from an edge thereof in the plane of the strip, twisting said teeth about their axes, bending the soformed twisted tooth strip into helical form, while maintaining the teeth in a substantialliy radial direction, severing the helix to prouce individual helical sections and simultaneously forming in the severed ends complemental locking members, and finally flattening the helix into circular form and interlocking said members together, for the purposes set forth.

2. The method of making a lock washer having radially directed, axially twisted locking teeth, which comprises severing a strip of ribbon metal lengthwise on an irregular line producin two stock stri having regular teeth pro ecting outwar y from an edge thereof 1n the plane of the strip, twisting said teeth about their axes, bending ture.

RICHARD T. HOSKING. 

